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<h1>class <span style="font-family: monospace;">GL.Texture</span></h1>
The Texture class in the GL submodule provides a context-independent
representation of an OpenGL texture. You can use a single Texture
object with multiple GLViews and/or GLPixmaps without being concerned
whether they are sharing texture spaces or not, and without having to
keep track of OpenGL texture numbers.<br>
<br>
Texture is an abstract class. To use it, you subclass it and define the
<span style="font-family: monospace;">do_setup</span>
method to make whatever OpenGL calls are necessary to set up the
texture. Then, when you want to draw with the texture, you call the <span style="font-family: monospace;">bind</span>
method to make it the current OpenGL texture. Whenever the Texture is
used in a context where it has not been used before, your <span style="font-family: monospace;">do_setup</span> method
will be called to create a representation of the texture appropriate to
that context.<br>
<br>
Keep in mind that any call to <span style="font-family: monospace;">bind</span>
can trigger allocation of a texture number and a call to your <span style="font-family: monospace;">do_setup</span>
method, and this will usually happen while you are in the middle of
doing OpenGL drawing. If this would be inconvenient, you may need to
"preload" the texture by calling the <span style="font-family: monospace;">bind</span> method
once in each context where the texture might be used, before you start
drawing.<br>
<h2>Constructor</h2>
<div style="margin-left: 40px;">
<dl>
<dt style="font-family: monospace;">Texture(texture_type)</dt>
<dd>Constructs a texture of the given type. The <span style="font-style: italic;">texture_type</span> should
be one of the OpenGL texture type constants (GL_TEXTURE_2D etc).<br>
</dd>
</dl>
</div>
<h2>Methods</h2>
<div style="margin-left: 40px;">
<dl>
<dt style="font-family: monospace;">bind()</dt>
<dd>Makes this
texture the current texture for the current context by calling
glBindTexture. If this texture has not previously been used
with the current context (or one with which it is sharing
textures), an OpenGL texture number is allocated and <span style="font-family: monospace;">do_setup</span> is
called to initialise a representation of the texture.<br><br></dd><dt style="font-family: monospace;">gl_id()</dt><dd>Returns
the OpenGL texture number corresponding to this texture in the current
context. May trigger allocation of a new texture and a call to <span style="font-family: monospace;">do_setup()</span>.
Does not bind the texture, unless a new texture is allocated, in which
case the current texture binding may be changed as a side effect.<br><br></dd><dt style="font-family: monospace;">gl_tex_image_2d(image, target = GL_TEXTURE_2D, internal_format = GL_RGBA,<br>&nbsp; &nbsp; &nbsp; &nbsp; border = False, with_mipmaps = False)</dt><dd>Loads the currently bound texture with data from an <a href="Image.html">Image</a>. You will typically call this from your <span style="font-family: monospace;">do_setup()</span> method to load the texture data. The image size is scaled up to a power of 2 if necessary. If <span style="font-family: monospace;">border</span> is true, the image will be assumed to have a 1-pixel wide border. If <span style="font-family: monospace;">with_mipmaps</span> is true, a set of mipmaps will be generated using <span style="font-family: monospace;">gluBuild2DMipmaps</span>.<span style="font-style: italic;"> Note:</span> <span style="font-family: monospace;">border</span> and <span style="font-family: monospace;">with_mipmaps</span> cannot both be true.<br></dd>
<dt style="font-family: monospace;">deallocate()</dt>
<dd>Deallocates any OpenGL resources currently allocated to the
Texture. If it is used again, new resources will be allocated.<br>
</dd>
</dl>
</div>
<h2>Abstract methods</h2>
<div style="margin-left: 40px;">
<dl>
<dt style="font-family: monospace;">do_setup()</dt>
<dd>This method should be implemented to make the necessary
OpenGL
calls to initialise the texture. When this method is called, a texture
number will already have been allocated and <span style="font-family: monospace;">glBindTexture</span>
called to make it the current texture.<br>
</dd>
</dl>
</div>
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